This deer mouse "singing" was recorded by Biologist Matina Kalcounis-Rueppell (University of North Carolina, Greensboro). One of her research interests is how bats and rodents use ultrasound.
http://www.uncg.edu/bio/faculty/matina_kalcounis/
In 2004, Kalcounis-Rueppell used hand-held recorders capable of recording ultrasonic emissions at a field site California. Later, while going through the recordings, which were played back at a lowered speed and frequency to make them more audible to humans, an unusual and loud sound was heard: this four-note song of a deer mouse.
For a complete story on this research follow this link:
http://www.smithsonianmag.com/science-nature/The-Mystery-of-the-Singing-Mice....
My lord that was spooky. And it made my cat get all perked up and confused.
RorschachRedemption 10 months ago